Lithium ion battery technology is becoming the standard for rechargeable energy storage systems. Lithium ion batteries are able to store up to three to four times as much electric energy as currently used rechargeable batteries.
However, current lithium ion battery pack balancing technology has the disadvantage that it requires complex and costly electronic control and balancing circuitry that may be inactive for long periods of time.
Accordingly, there exists a need for a method of extending the power duration of a battery pack using continuously active control circuits that are available for use at all times.
Currently, balancing the capacities of the series connected lithium ion cells in a battery pack system is accomplished using resistors connected by switches across each cell combined with cell voltage monitoring and computer control. The resistors dissipate a relatively small amount of power and are activated infrequently. Large battery packs with multiple sources and imbalance leak currents causing the battery pack capacity to diminish and not be available for rapid use at all times.
Therefore, a need exists to continuously minimize the loss of capacity of a large lithium ion battery pack system.
The present embodiments address these needs.
The present embodiments are detailed below with reference to the listed Figures.